The disclosure relates to the diagnosis and therapy of sleep disorders.
More particularly, the disclosure relates to a “kinesthetic stimulation” device which is a device for external sensory stimulation of the patient by a vibrator in contact with the skin in a sensitive and precise region of the body of the patient. Activating this vibrator has the effect of locally exciting cutaneous or mechanoreceptor endings of the skin, and triggering a response from the patient's autonomic nervous system, with sympathetic predominance (hereinafter “autonomic response”).
The autonomic response to sympathetic activation is observable on the major modulator effects of cardiac activity, for example a chronotropic effect (e.g., a heart rate increase, a decrease in RR intervals, etc.) and an inotropic effect (e.g., heart contractility increase, etc.). This autonomic response is also observable on the peripheral vasoconstriction, which is increased during sympathetic autonomic activation.
In addition to these effects on cardiac activity, a sympathetic activation causes responses in the respiratory system and/or in the central nervous system (autonomic awakenings).
Such a noninvasive technique acts on a number of sleep disorders in alternative ways to the conventional therapeutic approaches that are based on the application of a continuous positive airway pressure through a face mask (a therapy by CPAP), the use of a mandibular orthosis and/or electrical stimulation of the hypoglossal nerve, which involves the implantation of a pacemaker.
In particular, the respiratory disease known as “sleep apnea syndrome” (SAS) is characterized by the frequent occurrence (at least 10 to 20 times per hour) of apneas during a patient's sleep phase, an “apnea” (or respiratory pause) being defined as a temporary cessation of breathing for a duration longer than 10 s. SAS can also be characterized by the occurrence of hypopnea under the same conditions, a “hypopnea” being defined as a significant decrease (without interruption) of the breathing rate, typically a decrease of more than 50% compared to a previous reference average value.
This pathology reaches more than 4% of the population and more than 50% of patients with heart failure. To protect the individual against asphyxiation due to the decrease in blood oxygen concentration during the interruption or the reduction of respiratory rate, the body adapts itself but with a deleterious effect on sleep, causing unconscious micro-arousals. The consequence is daytime sleepiness in the wakeful stage, with loss of attention and increased risk of accident. Furthermore, several studies have shown a higher incidence of blood disorders such as hypertension, ventricular arrhythmias, myocardial infarction and heart failure in patients with SAS.
Several documents describe the ability to stop apnea episodes through a stimulation therapy. For example, U.S. Pat. No. 5,555,891 A describes a vibrotactile stimulation system to stop apnea in newborns. The objective is to provide a system capable of detecting apnea and of stimulating the child to stop apnea, with stimulation energy that may vary to avoid habituation. The applied energy is important and often involves arousal.
WO2007141345 A1 describes a remote monitoring system for neonatal units, to detect and stimulate infant apnea-bradycardia. This application refers to an adjustment of the stimulation energy based on the measured heart rate of the infant.
The initialization of the stimulation parameters is performed from a pre-established database and, therefore, does not take into account some physiological specificities of the patient (weight, gender, etc.), while clinical studies have demonstrated a relationship of the response to the kinesthetic stimulation, according to these physiological parameters.
WO 96/28093 A1 also teaches a system that delivers a stimulus to reduce the frequency or duration of an apnea episode. At the stimulation level, this document simply describes the low and high limits of the stimulation energy that may stop apnea without waking the patient.
WO 2009/154458 A2 teaches a system which detects apnea and in turn causes an inspiration reflex by stimulation in the ear region. Various apnea detection methods are cited, and stimulation may be electrical or mechanical. The stimulation strategy is simple, and involves applying pulse trains as long as the disorder is present. However, the stimulation parameters may vary without indicating rules of variation. A change in stimulation parameters to avoid habituation is also cited.
US 2010/0048985 A1 describes a similar device for applying stimuli by various natures (e.g., audio or ultrasonic stimulation of the ear, eye stimulation, mechanical stirrer, etc.). The device also analyzes respiratory activity to evaluate the effectiveness of the stimulation so that the patient or the physician can change the settings of the generator as desired with different stimuli doses.
Finally, US 2008/009915 A1 discloses a system that detects respiratory disorders using a nasal or other cannula and applies a particular vibratory stimulation in the ear region. The objective is to stop apnea, without waking the patient, by stimulation which may be manually or automatically adjusted, depending on physiological characteristics of the patient or of the sleep cycles. This document also generally cites the optimization of the stimulation parameters to fit the severity of the patient's disorder, without giving details on the stimulation parameters adjustment. A change in parameters to prevent habituation is also cited.